Brake for propeller drives



Feb. 15, 1955 o. v. MoNTlETH BRAKE FOR PROPELLER DRIVES 2 Sheets-Sheet 1 Filed April l, 1950 Feb. 15, 1955 0, v, M0NT|ETH 2,702,100

BRAKE FOR PROPELLER DRIVES /z W 'y l /Qja k l f/L/TJ? 2,702,100 Patented Feb. 15, 1055 BRAKE FOR PROPELLER DRIVES Oscar V. Montietli, Indianapolis, 1nd., asslgnor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application April l, 1950, Serial No. 153,361 8 Claims. (Cl. 18S- 110) This invention relates to aircraft propeller drives and more particularly to a braking system for aircraft propellers.

The invention is illustrated in conjunction with a contra-rotating dual pro ller drive gear. The propel- 1ers are driven by a sing e engine sha ft which drives the sun gear of a planetary gear train which positively drives the propellers in opposite directions. The sun gear meshes with planet pinions mounted on a spider connected to one propeller shaft. The planet pinions mesh with a ring or orbit gear fixed to the other propeller shaft. To prevent differential action the planet pinion has an vaiutiliary pinion rotating therewith and meshing with a ring gear fixed to the casing. Thus there is a positive gear connection between both propeller shafts and the drive shaft and a brake applied to one of these shafts would act on all of them. The propeller brake can then be connected by step-up gearing to the outer propeller shaft. The brake has a normally fixed conical drum which is engaged by a conical shoe. A spring constantly urges the shoe into engagement with the drum and iluid pres sure generally from the oil pump holds the brake in released position when the engine is operating. In order to release the brake before starting a source of auxiliary pressure is connected to the iluid actuating member to release the brake.

A primary object of this invention is to gravide, in a direct aircraft propeller drive mechanism, a rake to prevent the wind-milling of the propellers when they are feathered.

Another object of the invention is to provide in a propeller braking mechanism a spring-operated brake, wherein the brake shoe is spring-pressed iiito engagement with the drum during relative rotation in one direction, and where the brake is self-energized and ca mactuated for increased braking during relative rotation in the other direction.

Another object of the invention is to provide in a propeller drive mechanism a spring-actuated brake which is normally held in released position by power generated by the power plant for the propeller engine, and is held in released position for starting by an auxiliary power plant.

These and other objects of the invention will be apparent from the following drawings and specification which is illustrative of a preferred form of the invention.

In the drawings- 'Figure 1 is a fragmentary sectional view of a dual propeller drive and reduction gear with the brake.

Figure 2 is an enlarged fragmentary sectional view of the brake.

I Tigii'e 3 is an enlarged fragmentary developed view of a Cial.

The invention as illustrated in the drawings is eniployed in a proulsion system having a contra-rotating dual propeller riven by one engine unit. The drive shaft l0 is connected to a power plant, generally of the internal combustion t e, and is mounted in a bearing 12 secured in the gear ousin 14. The shaft 10 has an end portion 11 which ma a separate element secured to shaft 10 or an integral portion of shaft 10. The portion 11 has splines 16 at the end thereof on which the sun gear 18 is mounted. The spline 16 is of the floating type to allow axial movement of the sun gear 18 which is restrained by the planet carrier or spider 22.

The gear 18 meshes with a plurality of planet gears 20 tixed to a shaft 21 partially shown at the top of Figure l and mounted on the spider 22. "Ihe spider 22 has an inwardly extendinl supportigs frame 24 having hollow portions 26 for e gears The walls of spider 22 at each side of gears 20 have bearings 27 for shaft 21. The sgider has central solid portions 28 between the gears 2 to provide a base for the bolts 30 and oil passages. The spider 22 is recessed at 32 throughout the solid rtions 28 to provide clearance for the sun gear 18. e recess is closed at one side by a Bange 34 which is secured to the inner edge of the spider 2 and has sealiitilg1 engagement with one side of the hub of gear 18. At e other side the inner edge of the spider has an integrally extending Bange 36 which extends into contact with the other side of the hub of the gear 18 to rovide a closed chamber surroundin the gear 18.

e spider 2 has an annular oil recess 8 which mates with an ann ve 40 in a fixed portion 42 of the casing. Lubrica oil from ump 174 or any central source is supplied y a pipe w ich is not shown in this section to the passage 44 which communicates with the grooves 40 an 38. From the groove 38 the oil flows through a suitable main passage 46 and is distributed to the gear by the passages 48 and to one flange seal by the passage 50 illustrated below the center of shaft llfand to the other flange seal by the passage 52 illustrated above the center of shaft 11.

'I'he spider 22 is mounted on an annular supporting plate 56 which is secured to the end of the inner propeller shaft 58. The inner propeller shaft is mounted in ball bearing 60 which is secured inside the outer propeller shaft 62. '111e two propeller shafts are mounted concentrically and rotate in opposite directions, and are supported in bearing 66 which is secured in partition 64 of the gear-box 14. The shaft 58 is connected to the forward propeller and the shaft 62 to the aft propeller of a pair of oppositely rotating propellers.

The outer shaft 62 has an annular radially and axially offset flange 68 at the end thereof. This flange surrounds the spider 22 and supports the annular or ring gear 70 which meshes with the planet gears 20 of the reduction gear drive. In order to prevent differential movement between the two propellers the planetary gearing is connected to the casing 14. An auxiliary planetary geai 69 i s positioned on each planetary gear shaft 21. This auxiliary gear 69 meshes at the outer side of spider 22 with a fixed ring gear or auxili orbit gear 71 which is secured to the housing 14 as s own in the lower portion of Figure l.

A brake gear 72 is also attached to this end of the outer propeller shaft 62. The gear 72 meshes with a pinion 74 on the brake shaft 76 which is mounted in the bearing 78 secured in an aperture in the supporting partition 64. Adjacent the partition 64 a gear 80 s secured to the shaft 76. The gear 80 meshes with a pinion 82 on a countershaft 84 su ported in partition 64 and support 92 and displaced hind the brake mechanism as shown in Figure 1. The countershaft has a gear 86 driving the braking sleeve pinion 90. The brake mechanism is mounted on a support 92 which has an open bearing support 94 which supports the bearing 96 for the end of the brake shaft 76.

The support 92 has a central aperture to receive a bearing support and cam member 98. The bearing su port member 98 has flanges at each side to support e bearings 102 for the brake sleeve 104 which is driven by the pinion 90. The central support 98 has a c lindrical guide portion 106 which is slidably engage `by the central flange 107 of the brake drum 110 in order slidably support the brake drum 110 concentric with sleeve 104. A series of pins 108 are secured about the perimeter of the support member 98 to limit the rotational movement of the conical brake drum 110. The pins 108 engage the drum 110 by passing through an elongated slot in the flange 112. Coil springs 114 positioned around the pins 108 and held in position by an abutment or nut 116 engage the ange 112 and urge the drum to slide toward the support member 98. The su port member 98 has a series of cams 118 and the bra e member has an interengaging and complementary series of cams 120 illustrated in Figure 3. so that relative roy be employed and connected to the hydraulic 8 tations!movementoftliebrakedruirn110wlthi'espectl to the support 98 will produce axial displacement between the members and compress springs 114.

A brake drum tube 122 is mounted within the brake sleeve 104 and the tube and sleeve have interengagin lines 123 to revent relative rotation but allow axi The tu 122 has annular llange 124 constituting a rake disc to support the frustro-conical brake shoe 126. 'I'he brake tube 122 has an enlarged cylindrical portion 128 adiacent the brake shoe supportinug flange 124 which is s dably mounted about a hydra ic connector 130 of cylindrical form which has suitable seals 132. The hydraulic connector 130 is suitably secured to a support portion 134 of the housing 14. The central passage in the brake tube 122 is closed at the other end and an utment or spanner nut 136 is secured thereto. A dual il spring 138 is compressed between the abutment 186 and the end of the sleeve 104 to bias the brake shoe toward braking position.

The hollow center of the brake tube 122 is connected to the piston chamber 142 by means of a passage 144. The piston chamber has a back wall 146 consisting of an annular plate secured to the brake sleeve 104 and sealed to the inner c lindrical surface of the conical brake shoe 126 b a rub r seal 148. Aligned oil assages 152 in the tu 122 and olaassage 154 in the s eeve 104 allow oil to tlow to the b e for cooling when the brake is in or near the applied position.

The engine driven shaft has a gear 160 secured thereon just inside the housing 14. The gear 160 meshes with idler 162 which is mounted in suitable bearigs in the gear housing 14 and the partition 164. e idler 162 drives gear 166 which is mounted on shaft 168 which is also supported in suitable bearings in the gearbox 14 and the partition 164. The shaft 168 has a bevel gear 170 secured thereon which meshes with a bevel gear 172 which drives the multiple-bank gear pump 174. The inlet pipe 176 of the gear lpump terminates in a strainer portion located in the ower part or sump of the gear housing 14. A forward pipe 178 extends from the gear pump forward through the sump portion of gear housing 14 and through the partition 64 to a passage 179 in the forward end of the housing. This inlet passage opens into the forward end of the housing to scavenge the oil when the housing is in clined such as in a dive. A pump outlet pipe 181 extends across the housing 14 and is connected with a bored oil passage 180 in the gear housing beneath the brake. The passage 180 leads to a one-way or check valve 182 through which oil may ilow to the chamber 184. A check valve 186 positioned in a conduit 188 leading from an auxiliary source of fluid pressure, such as pump 189, is positioned in another wall of the chamber 184. A passage 190 leads from the chamber 184 to the connector 130 in order to supply oil to the brake mechanism. If two brakes are required to ly sufticient braking torque, a second duplicate b e may System The power plant which may consist of one or more engines islsconfnecteill to the shaftdu? and lrivesd the sun gear o a panetary rope er uction drive. One propeller itsyprenounteii) on the inner sleeve shaft 58 which is driven by a spider supporting the planetary which mesh with the sun gear 18. A secon propeller is mounted on the external sleeve shaft 62 which is connected to the annular ring gear or orbit gear 70 which meshes with the gears 20.

The planetary gears have auxiliary gears rotating on the same shafts mounted on the spider connected to shaft 58. The auxiliary gears mesh with a xed orbit gear or ring gear mounted in the gear housing so that the planetary gearing provides a positive contra-rotating drive for the dual propellers.

The brake mechanism is connected to the outer sleeve shaft 62 by a series of step-up gearing starting with the gear 72 fixed to shaft 62 and driving the aligned brake shaft 76 by meshing with pinion 74. The drive continues through gear 80 lxed to the shaft 76 which drives a countershaft pinion 82 mounted on countershaft 84. From the countershaft the drive is transferred from gear 86 to pinion 90 which drives the brake sleeve. Thus the brake rotates at many times the speed of the propellerahaftandthebrakingforcenecessarytostoppumpconnectedto 'passage 144 to 4 tbepwerslsreduced. lnthisdesignthebr'akerotaies a ut 30 times faster than the propeller.

In normal operation this gear drive rotates with the outer propeller shaft. The brake shoe which is mounted on the brake tube 122 is held in released tion by uid pressure generated iii the oil pump m durin the normal operation of e propeller drive. 'l'lie o is supplied from the pump through pipe 181, 180 and check valve 182. From the check v ve y oil enters the chamber 184 and Bows up through the connector 1 30 to the hollow interior of the tube 122 which 1s slidably mounted in the sleeve 104. The oil ilowii through aperturea? :had egedrsbthe chamber 142 crea ng a pressure ag t e ac late 146 and the brake lian 124 and movesr thekills shoe 126 am:h the 13s compressing e sprin When there is engge failure and it is necessary to feather and .stop the Propellers, the pump 174' ceases to lpump huid to the brake cylinder or chamber 142 to old the brake in released 138 o crates and pulls conical shoe 126 into contact with e brake drum 110. 'I'he oil escapes from the operating cylinder 142 through holes 152 and 154 and by leakage eaisst the seal 148, by leakage past ring seals 132, by l age through the clearance between sleeve 104 and tube l122. When the shoe 126 is just about to engage the drum 110, the aperture 152 in the brake tube 122 and aperture 154 in the brake sleeve 104 come into alignment and allow oil to llow between the wall146 andthe time 107 to the brakin g surfaces for cooling. This oil fall'into the housing 14 aad return to the sump. If the propeller tends to rotate in the normalldirection, the ratchet cams 118 and 120 lock and revent relative rotation of the brake drum 11-0 and e support member 98. Then the brake is merel actuated by the spring 138. However, if the prop er tends to rotate in a reverse direction and thus rotates the brake shoe 126 in reverse direction, the shoe would drag the drum in this direction, and the cams 118 and 120 will ride up on each other and the drum will be forced away from the support 98 to further increase the braking pressure and thus the braking eect. When the reverse rotation ceases the springs 114 will return the brake drum 110 to the normal position.

In order to start the engine which may be of the internal combustion en e type such as a gas turbine, this propeller b e must be released. This is accomplished with an independent source of huid pressure, such as auxiliary pump 189, which is connected to the conduit 188. In starting the engine the auxiliary pressure is built up until it opens the check valve 186 and enters the chamber 184. The check valve 182 will remain closed or be closed so that oil liow to theoil sump 174 will be prevented. Thus the independent oil ow will move upward through the connector and e cylinder 142 to release the brake.

As the engine is started the oil {um 174 will create a pressure sufiicient to open chec v ve 182 and close check valve 186 and maintain the brake in released position. The independent source of lluid pressure may then be cut oil.

The above described embodiment is illustrative of the invention which is subiect'to many modiications within the scope of the appended claims.

Certain structure disclosed but not claimed in this application is disclosed and claimed in the applications, ofcomnion ownership with this apgication, of Victor W. Peterson for Propeller Drives, rial No. 231,465, filed June 14, 1951 (a continuation-mart of abandoned application Serial No. 128,427 ed November 19, 1949) and of William R. Bain for Pro ller Brake Sytem, Serial No. 171,741, lled July l. l 50.

claim:

l. In an aircraft engine drive, a propeller drive shaft, a lirst pump connected to said drive shaft, a propeller brake connected to said drive shaft to stop said drive shaft, hydraulic means to release said propeller brake, a rst check valve, duid supply means from said first punti connected to said hydraulic means through the first chec valve. an auxiliary pump capable of supplying hydraulic tiuid when said drive shaft is not rotating, a second check valve, a second lluid supply means from said auxiliary said hydraulic means through the brak rake tube assembly 122 to the lef: l

position. Then the spring' second check valve,

rotated, a propeller brake having a fixed part and a4 rotary part, means connecting said propeller drive means to said rotary part to rotate said rotary part about thirty times the speed of said propeller drive to reduce the amount of force required to stop the propeller rotation, and brake applying means cooperating with said fixed part and said rotary part to stop said rotary part and said propeller.

3. In an aircraft engine drive, a support, propeller drive means, a brake member mounted for rotation and axially fixed in the support and connected to said propeller drive means, a brake drum mounted for rotary and axial movement on said support, means on said drum and support preventing rotation in one direction and allowing limited rotation in the other direction with axial movement, a tube slidably mounted in said member and in rotary driving relation thereto, a brake disc cooperating with said brake drum-supported on the tube, means between said member and said disc to form a chamber therebetween, and fluid pressure supply means connected to said chamber.

4. In an aircraft engine drive, a propeller drive shaft, a ropeller connected to said propeller drive shaft, power ta e-o means connected to said drive shaft, a propeller brake connected to said drive shaft, means to release said propeller brake, connecting means connecting said power take-off means to said release means to release said propeller brake, auxiliary power means to supply power when said propeller drive shaft is not rotating, connecting meansconnecting said auxiliary power means to said brake release means to release said brake when said propeller drive shaft is not rotating, and means in said connecting means to disconnect said auxiliary power means from said brake release means operated by said power tak-o means being effective to release said propeller bra e.

5, In an aircraft engine drive, a support, propeller drive means, a brake member mounted for rotation and axially fixed in the support and connected to said propeller drive means for rotation therewith, a brake drum mounted for rotary and axial movement on said support, means on said drum and support preventing rotation in one direc tion and allowing limited rotation in the other direction with axial movement, la tube vslidably mounted in said member and in rota driving relation thereto, a brake disc supported on sad tube for cooperation with said drum, spring means between said tube and said member to move said brake disc toward said drum, means between said member and said disc to form a chamber there-V 8 between, and huid pressure suply means connected to said chamber to retract said bra e disc from said drum.

6. In an aircraft engine drive. a support, ropeller drive means, a brake member mounted for rotat on and axially fixed in the sup rt and connected to said propeller drive means for rotat on therewith, a brake drum mounted for rotary and axial movement on said' support, means on said dnim and luplport preventing rotation in one direction and allowing imited rotation in the other direction with axial movement, a tube slidably mounted in said member and in rotary drivin relation thereto, a brake disc supported on one end o said tube for cooperation with said drum, spring means between the otherA end of said tube and said member to move said brake disc toward said drum, means between said member and said disc to form a chamber therebetween, and fluid pressure supply means connected to said chamber to retract said brake disc from said drum.

7. In an aircraft engine drive, a support, propeller drive means, a brake member mounted for rotation and axially fixed in the support and connected at one end to said rotary drive means for rotation therewith, a brake drum mounted for propeller and axial movement on said support, means on said drum and support preventing rotation in one direction and allowing limited rotation in the other direction with axial movement, a tube slidably mounted in said memberand in rotary driving relation thereto, a brake disc supported on one end of said tube, spring means between the other end of said tube and said member adiacent said drive means to move said brake disc toward said drum, means between said member and said disc to form a chamber therebetween, and fluid pressure supply means connected to said chamber to retract said brake disc from said drum.

8. In an aircraft engine drive, a support, propeller drive means, a brake member mounted for rotation and axially fixed in the support and connected at one end to said propeller drive means for rotation therewith, a brake drum mounted for rotary and axial movement on said support, means on said drum and support preventing rotation in one direction and allowing limited rotation in the other direction with axial movement, a tube slidably mounted in said member and in rotary driving relation thereto, a brake disc supported on one end of said tube, spring means between the other end of said tube and said member adiacent said drive means to move said brake disc toward said drum, and means acting on said brake disc to retract said brake disc from said References Cited in the file of this patent UNITED STATES PATENTS 1,561,722 Iimerson Nov. 17. 1925 2,144,423 Caldwell Jan. 17, 1,939 2,304,560 Freeman 1942 2,482,460 Browne Sept. 20, 1949 

